Vegetation types of East Ladakh: species and growth form composition along main environmental gradients

Abstract

Question: The vegetation of high mountain regions in Himalaya remains poorly assessed despite the expected vulnerability of these ecosystems to global change drivers. What are the main vegetation types in East Ladakh and which environmental factors influence the species composition and growth forms distribution? Location: The south-westernmost extension of the Tibetan Plateau, an arid mountainous area, in East Ladakh, Jammu & Kashmir State, India. Methods: Species composition was recorded for 369 plots (each 100 m2). Plots, sampled from 4180 m a.s.l. (bottom of the Indus Valley) up to 6060 m a.s.l. (close to the snowline), covered a wide range of environmental conditions. Results: TWINSPAN clusters discriminated eight ecologically interpretable vegetation types, corresponding to the main habitats in the area: animal resting places, salt marshes, semi-deserts and steppes, shrublands, alpine screes and boulder fields, alpine grasslands, water bodies and subnival zone. The most important environmental factors influencing the species composition were altitude, soil moisture and salinity. Screes and alpine grasslands were found to be the most species-rich. The species were ranged into 20 growth forms with regard to life-form and clonality, with growth forms showing different changes in proportion among vegetation types and along the different environmental gradients. Conclusion: The study summarizes the main vegetation types of East Ladakh in terms of species and growth form compositions. The results can have a heuristic value for designing future monitoring schemes and assess the effects of global change in these diverse, but poorly studied, regions.